Dietary and Planetary Health

The relationship between dietary health and planetary health seems unlikely to fade from public view. A new study published by scientists from Cornell, Syracuse, and Tufts finds different diets have an enormous impact on sustainable land use. By modeling the impact of different diets, the researchers found that the average American diet cuts the capacity of available land to feed the population by more than half.

The researchers modeled the effects of different alternatives to the current average American diet. Eight of the nine different scenarios were consistent with the 2015 Dietary Guidelines for Americans. But those scenarios had widely varying effects on how many people could be fed from a given amount of land. Senior Author Gary Fick, a professor of crop sciences at Cornell, explained:

We know that, in many ways, land use can have severe ecological impacts, for example, biodiversity loss; an extreme and inequitable competition for land, water and energy; and carbon emissions, an adverse impact of converting corn to biofuels. Before we go about converting land to other uses, to develop sound agricultural policy, we have to understand the impact of dietary patterns on land use. We don’t want to short-change the equitable distribution of nutritious, life-sustaining foods to the whole population.

Production of meat and animal by-products (dairy, eggs, honey) is a variable that has significant effects. Diets including some meat can feed more people than vegan diets, depending on estimates of how much land is suitable for crop cultivation. Overall, diets with less meat led to the more efficient land use. A vegetarian diet that includes dairy products was the most efficient.

China has had to face the environmental impact of dietary recommendations. Inevitably, the U.S. and other countries must do so as well. Healthy people need a healthy planet.